<!doctype html>
<style>
p {display:table} /* makes reference image smaller */

.t.n.f.r:not(.v),  .\"a.\'b
{
	color: blue
}
</style>

<p class="&#9;t &#10;n &#11;v &#12;f &#13;r">blue
<p class="&quot;a 'b">blue  <!-- this fails if split_string is used with nonempty quote (the default), see html_tag::set_attr -->